The present invention is generally directed to intermediates useful in the preparation of compounds useful in therapy. More specifically, the present invention relates to intermediates useful in the preparation of a class of fused polycyclic alkaloids. The invention also relates to methods for the preparation of the fused polycyclic alkaloids and their analogues and derivatives.
Naturally occurring molecules which exhibit potentially beneficial pharmacological properties are isolable from a range of environments, such as marine, plant and microbial sources. One example of such molecules is the general class of compounds known as the Lamellarins. These polyaromatic alkaloids are, isolated from marine sources and comprise a fused framework. Lamellarins C and D have been shown to cause inhibition of cell division in fertilised sea urchin assay, whereas Lamellarins I, K and L all exhibit comparable and significant cytoxicity against P388 and A549 cell lines in culture. Recently, Lamellarin N has been shown to exhibit activity in lung cancer cell lines by acting as a Type IV microtubule poison. Furthermore, these compounds have also been shown to possess cytotoxic activity on multidrug resistant cells as well as efficacy as non-toxic modulators of the multidrug resistant phenotype and, therefore, afford an attractive potential source of chemotherapeutic agents.
However, the potential clinical usefulness of the Lamellanins is severely limited by the modest quantities produced naturally as well as the difficulties involved in their isolation.
There has accordingly, been significant activity directed towards the development of a synthetic route to this class of molecules, and approaches to these molecules have included a sequential double cyclization of a 1,3,4-triaryl-2,5-dicarboxysubstituted pyrrole ring (Steglich et al, Angew., Chem. Int. Ed. Eng. 1997, 36, 155), and N-ylide-mediated pyrrole ring formation to install the pyrrole and lactone portions of the molecule (Banwell et al, Chem. Commun., 1997, 2259) Ishibashi et al, Tetrahedron, 1997, 53, 5951).
The present invention now provides an alternative method via a synthetic intermediate, which allows for the incorporation of a range of substitution patterns and potentially permits access to a variety of Lamellarin compounds and analogues containing the fused polycyclic-pyrrole core.
Accordingly, in a first aspect the invention relates to a method for the preparation of a compound of Formula (II). 
comprising the step performing an intramolecular cyclization of a compound of Formula (I): 
wherein:
RA1-A4 are each independently selected from hydrogen, optionally substituted alkyl optionally substituted alkenyl, optionally substituted alkynyl, optionally protected hydroxy, optionally substituted amino, optionally substituted alkoxy, optionally substituted alkenoxy, optionally substituted alkynoxy, optionally substituted aryl, optionally substituted heterocyclyl, carboxy, carboxy ester, carboxamido, acyl, acyloxy, mercapto, optionally substituted alkylthio, halogen, nitro, sulfate, phosphate and cyano; or
RA2 and RA3 may optionally together form a bond and RA1 and RA4 are as defined above or together with the carbon atoms to which they are attached form an optionally substituted carbocyclic or heterocyclic group; or
RA2 and RA3, together with the carbon atoms to which they are attached form an optionally substituted saturated or unsaturated carbocyclic or heterocyclic group; or
RA1RA2Cxe2x80x94CRA3RA4 forms an optionally substituted aryl group or aromatic heterocyclic group;
Y is selected from hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally protected hydroxy, optionally substituted amino, optionally substituted alkoxy, optionally substituted alkenoxy, optionally substituted alkynoxy, optionally substituted aryl, optionally substituted heterocyclyl, carboxy, carboxy ester, carboxamido, acyl, acyloxy, mercapto, optionally substituted alkylthio, halogen, nitro, sulfate, phosphate and cyano;
W and X are as defined for Y, or together with the nitrogen and carbon atoms to which they are attached, form a saturated or unsaturated nitrogen containing heterocyclic group which may be optionally substituted or optionally fused to a saturated or unsaturated carbocyclic group, aryl group or heterocyclic group;
V represents a halogen or hydrogen atom;
Z is xe2x80x94(CH2)nxe2x80x94Uxe2x80x94(CH2)oxe2x80x94 where U is selected from CH2, NH or a heteroatom, and n and o are independently selected from 0, 1, 2 or 3.
In a second aspect, the present invention provides an intermediate compound useful in the preparation of compounds of Formula (II), wherein said intermediate is of Formula (I): 
wherein:
RA1-A4 are each independently selected from hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally protected hydroxy, optionally substituted amino, optionally substituted alkoxy, optionally substituted alkenoxy, optionally substituted alkynoxy, optionally substituted aryl, optionally substituted heterocyclyl, carboxy, carboxy ester, carboxamido, acyl, acyloxy, mercapto, optionally substituted alkylthio, halogen, nitro, sulfate, phosphate and cyano; or
RA2 and RA3 may optionally together form a bond and RA1 and RA4 are as defined above or together with the carbon atoms to which they are attached form an optionally substituted carbocyclic or heterocyclic group; or
RA2 and RA3, together with the carbon atoms to which they are attached form an optionally substituted saturated or unsaturated carbocyclic or heterocyclic group; or
RA1RA2Cxe2x80x94CRA3RA4 forms an optionally substituted aryl group or aromatic heterocyclic group;
Y is selected from hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally protected hydroxy, optionally substituted amino, optionally substituted alkoxy, optionally substituted alkenoxy, optionally substituted alkynoxy, optionally substituted aryl, optionally substituted heterocyclyl, carboxy, carboxy ester, carboxamido, acyl, acyloxy, mercapto, optionally substituted alkylthio, halogen, nitro, sulfate, phosphate and cyano;
W and X are as defined for Y, or together with the nitrogen and carbon atoms to which they are attached, form a saturated or unsaturated nitrogen containing heterocyclic group which may be optionally substituted or optionally fused to a saturated or unsaturated carbocyclic group, aryl group or heterocyclic group;
V represents a halogen or hydrogen atom;
Z is xe2x80x94(CH2)nxe2x80x94Uxe2x80x94(CH2)oxe2x80x94 where U is selected from CH2, NH or a heteroatom, and n and o are independently selected from 0, 1, 2 or 3.
Yet a further aspect of the present invention relates to compounds of Formula (II) as defined above, prepared by the methods described herein.
As used herein the term xe2x80x9calkylxe2x80x9d, denotes straight chain, branched or cyclic fully saturated hydrocarbon residues. Unless the number of carbon atoms is specified the term preferably refers to C1-20 alkyl or cycloalkyl. Examples of straight chain and branched alkyl include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, amyl, isoamyl, sec-amyl, 1,2-dimethylpropyl, 1,1-dimethyl-propyl, hexyl, 4-methylpentyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, 3,3-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 1,2,2,-trimethylpropyl, 1,1,2-trimethylpropyl, heptyl, 5-methoxyhexyl, 1-methylhexyl, 2,2-dimethylpentyl, 3,3-dimethylpentyl, 4,4-dimethylpentyl, 1,2-dimethylpentyl, 1,3-dimethylpentyl, 1,4-dimethyl-pentyl, 1,2,3,-trimethylbutyl, 1,1,2-trimethylbutyl, 1,1,3-trimethylbutyl, octyl, 6-methylheptyl, 1-methylheptyl, 1,1,3,3-tetramethylbutyl, nonyl, 1-, 2-, 3-, 4-, 5-, 6- or 7-methyl-octyl, 1-, 2-, 3-, 4- or 5-ethylheptyl, 1-, 2- or 3-propylhexyl, decyl, 1-, 2-, 3-, 4-, 5-, 6-, 7- and 8-methylnonyl, 1-, 2-, 3-, 4-, 5- or 6-ethyloctyl, 1-, 2-, 3- or 4-propylheptyl, undecyl, 1-, 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-methyldecyl, 1-, 2-, 3-, 4-, 5-, 6- or 7-ethylnonyl, 1-, 2-, 3-, 4- or 5-propylocytl, 1-, 2- or 3-butylheptyl, 1-pentylhexyl, dodecyl, 1-, 2-, 3-, 4-, 5-, 6-, 7-, 8-, 9- or 10-methylundecyl, 1-, 2-, 3-, 4-, 5-, 6-, 7- or 8-ethyldecyl, 1-, 2-, 3-, 4-, 5- or 6-propylnonyl, 1-, 2-, 3- or 4-butyloctyl, 1-2-pentylheptyl and the like. Examples of cyclic alkyl include mono- or polycyclic alkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl and the like.
As used herein the term xe2x80x9calkenylxe2x80x9d denotes groups formed from straight chain, branched or cyclic hydrocarbon residues containing at least one carbon-carbon double bond including ethylenically mono-, di- or poly-unsaturated alkyl or cycloalkyl groups as previously defined. Unless the number of carbon atoms is specified the term preferably refers to C1-20 alkenyl. Examples of alkenyl include vinyl, allyl, 1-methylvinyl, butenyl, iso-butenyl, 3-methyl-2-butenyl, 1-pentenyl, cyclopentenyl, 1-methyl-cyclopentenyl, 1-hexenyl, 3-hexenyl, cyclohexenyl, 1-heptenyl, 3-heptenyl, 1-octenyl, cyclooctenyl, 1-nonenyl, 2-nonenyl, 3-nonenyl, 1-decenyl, 3decenyl, 1,3-butadienyl, 1-4,pentadienyl, 1,3-cyclopentadienyl, 1,3-hexadienyl, 1,4-hexadienyl, 1,3-cyclohexadienyl, 1,4-cyclohexadienyl, 1,3-cycloheptadienyl, 1,3,5-cycloheptatrienyl and 1,3,5,7-cyclooctatetraenyl.
As used herein the term xe2x80x9calkynylxe2x80x9d denotes groups formed from straight chain, branched or cyclic hydrocarbon residues containing at least one carbon-carbon triple bond including ethynically mono-, di- or poly- unsaturated alkyl or cycloalkyl groups as previously defined. Unless the number of carbon atoms is specified the term preferably refers to C1-20 alkynyl. Examples include ethynyl, 1-propynyl, 2-propynyl, and butynyl isomers, and pentynyl isomers.
The terms xe2x80x9calkoxy, xe2x80x9calkenoxy and xe2x80x9calkynoxy respectively denote alkyl, alkenyl and alkynyl groups as hereinbefore defined when linked by oxygen.
The term xe2x80x9chalogenxe2x80x9d denotes fluorine, chlorine, bromine or iodine.
The term xe2x80x9carylxe2x80x9d denotes single, polynuclear, conjugated and fused residues of aromatic hydrocarbon ring systems. Examples of aryl include phenyl, biphenyl, terphenyl, quaterphenyl, naphthyl, tetrahydronaphthyl, anthracenyl, dihydroanthracenyl, benzanthracenyl, dibenzanthracenyl, phenanthrenyl, fluorenyl, pyrenyl, idenyl, azulenyl, chrysenyl.
The term xe2x80x9cheterocyclicxe2x80x9d denotes mono- or polycarbocyclic groups, including aryl, wherein at least one carbon atom is replaced by a heteroatom, preferably selected from nitrogen, sulphur and oxygen. Where the mono- or polycarbocyclic group which has at least one carbon atom replaced by a heteroatom is an aryl group, this is referred to as a aromatic heterocyclic group.
Suitable heterocyclic groups include N-containing heterocyclic groups, such as,
unsaturated 3 to 6 membered heteromonocyclic groups containing 1 to 4 nitrogen atoms, for example, pyrrolyl, pyrrolinyl, imidazolyl, imidazolinyl, pyrazolyl, pyridyl, pyrimidinyl, pyrazinyl, pyridazinyl, triazolyl or tetrazolyl;
saturated 3 to 6-membered heteromonocyclic groups containing 1 to 4 nitrogen atoms, such as, pyrrolidinyl, imidazolidinyl, piperidyl, pyrazolidinyl- or piperazinyl;
condensed saturated or unsaturated heterocyclic groups containing 1 to 5 nitrogen atoms, such as, indolyl, isoindolyl, indolinyl, isoindolinyl, indolizinyl, isoindolizinyl, benzimidazolyl, quinolyl, isoquinolyl, indazolyl, benzotriazolyl, purinyl, quinazolinyl, quinoxalinyl, phenanthradinyl, phenathrolinyl, phthalazinyl, naphthyridinyl, cinnolinyl, pteridinyl, perimidinyl or tetrazolopyridazinyl;
saturated 3 to 6-membered heteromonocyclic groups containing 1 to 3 oxygen atoms, such as tetrahydrofuranyl, tetrahydropyranyl, tetrahydrodioxinyl,
unsaturated 3 to 6-membered hetermonocyclic group containing an oxygen atom, such as, pyranyl, dioxinyl or furyl;
condensed saturated or unsaturated heterocyclic groups containing 1 to 3 oxygen atoms, such as benzofuranyl, chromenyl or xanthenyl;
unsaturated 3 to 6-membered heteromonocyclic group containing 1 to 2 sulphur atoms, such as, thienyl or dithiolyl;
unsaturated 3 to 6-membered heteromonocyclic group containing 1 to 2 oxygen atoms and 1 to 3 nitrogen atoms, such as, oxazolyl, oxazolinyl, isoxazolyl, furazanyl or oxadiazolyl;
saturated 3 to 6-membered heteromonocyclic group containing 1 to 2 oxygen atoms and 1 to 3 nitrogen atoms, such as, morpholinyl;
unsaturated condensed heterocyclic group containing 1 to 2 oxygen atoms and 1 to 3 nitrogen atoms, such as, benzoxazolyl or benzoxadiazolyl;
unsaturated 3 to 6-membered heteromonocyclic group containing 1 to 2 sulphur atoms and 1 to 3 nitrogen atoms, such as, thiazolyl, thiazolinyl or thiadiazoyl;
saturated 3 to 6-membered heteromonocyclic group containing 1 to 2 sulphur atoms and 1 to 3 nitrogen atoms, such as, thiazolidinyl; and
unsaturated condensed heterocyclic group containing 1 to 2 sulphur atoms and 1 to 3 nitrogen atoms, such as, benzothiazolyl or benzothiadiazolyl.
The term xe2x80x9cacylxe2x80x9d refers to a carboxylic acid residue wherein the OH is replaced with a residue, for example, as defined for W, X, and Y and specifically may denote carbamoyl, aliphatic acyl group or acyl group containing an aromatic ring, which is referred to as aromatic acyl or a heterocyclic ring, which is referred to as heterocyclic acyl, preferably C1-20 acyl. Examples of suitable acyl include carbamoyl; straight chain or branched alkanoyl such as formyl, acetyl, propanoyl, butanoyl, 2-methylpropanoyl, pentanoyl, 2,2-dimethylpropanoyl, hexanoyl, heptanoyl, octanoyl, nonanoyl, decanoyl, undecanoyl, dodecanoyl, tridecanoyl, tetradecanoyl, pentadecanoyl, hexadecanoyl, heptadecanoyl, octadecanoyl, nonadecanoyl and icosanoyl; alkoxycarbonyl such as methoxycarbonyl, ethoxycarbonyl, t-butoxycarbonyl, t-pentyloxycarbonyl and heptyloxycarbonyl; cycloalkylcarbonyl such as cyclopropylcarbonyl cyclobutylcarbonyl, cyclopentylcarbonyl and cyclohexylcarbonyl; alkylsulfonyl such as methylsulfonyl and ethylsulfonyl; alkoxysulfonyl such as methoxysulfonyl and ethoxysulfonyl; aroyl such as benzoyl, toluoyl and naphthoyl; aralkanoyl such as phenylalkanoyl (e.g. phenylacetyl, phenylpropanoyl, phenylbutanoyl, phenylisobutylyl, phenylpentanoyl and phenylhexanoyl) and naphthylalkanoyl (e.g. naphthylacetyl, naphthylpropanoyl and naphthylbutanoyl]; aralkenoyl such as phenylalkenoyl (e.g. phenylpropenoyl, phenylbutenoyl, phenylmethacryloyl, phenylpentenoyl and phenylhexenoyl and naphthylalkenoyl (e.g. naphthylpropenoyl, naphthylbutenoyl and naphthylpentenoyl); aralkoxycarbonyl such as phenylalkoxycarbonyl (e.g. benzyloxycarbonyl); aryloxycarbonyl such as phenoxycarbonyl and napthyloxycarbonyl; aryloxyalkanoyl such as phenoxyacetyl and phenoxypropionyl; arylcarbamoyl such as phenylcarbamoyl; arylthiocarbamoyl such as phenylthiocarbamoyl; arylglyoxyloyl such as phenylglyoxyloyl and naphthylglyoxyloyl; arylsulfonyl such as phenylsulfonyl and napthylsulfonyl; heterocycliccarbonyl; heterocyclicalkanoyl such as thienylacetyl, thienylpropanoyl, thienylbutanoyl, thienylpentanoyl, thienylhexanoyl, thiazolylacetyl, thiadiazolylacetyl and tetrazolylacetyl; heterocyclicalkenoyl such as heterocyclicpropenoyl, heterocyclicbutenoyl, heterocyclicpentenoyl and heterocyclichexenoyl; and heterocyclicglyoxyloyl such as thiazolylglyoxyloyl and thienylglyoxyloyl.
The term xe2x80x9cacyloxyxe2x80x9d refers to acyl, as herein before defined, when linked by oxygen.
In this specification xe2x80x9coptionally substitutedxe2x80x9d is taken to mean that a group may or may not be further substituted or fused (so as to form a condensed polycyclic group) with one or more groups selected from alkyl, alkenyl, alkynyl, aryl, halo, haloalkyl, haloalkenyl, haloalkynyl, haloaryl, hydroxy, alkoxy, alkenyloxy, aryloxy, benzyloxy, haloalkoxy, haloalkenyloxy, haloaryloxy, nitro, nitroalkyl, nitroalkenyl, nitroalkynyl, nitroaryl, nitroheterocyclyl, amino, alkylamino, dialkylamino, alkenylamino, alkynylamino, arylamino, diarylamino, benzylamino, dibenzylamino, acyl, alkenylacyl, alkynylacyl, arylacyl, acylamino, diacylamino, acyloxy, alkylsulphonyloxy, arylsulphenyloxy, heterocyclyl, heterocycloxy, heterocyclamino, haloheterocyclyl, alkylsulphenyl, arylsulphenyl, carboalkoxy, carboaryloxy mercapto, alkylthio, benzylthio, acylthio, cyano, nitro, sulfate and phosphate groups. The term xe2x80x9coptionally protectedxe2x80x9d is taken to mean that a group such as a hydroxy group may or may not be protected by a protecting group. Suitable protecting groups are known and examples thereof are described in Protective Groups in Organic Synthesis, by T. W. Greene, (1981), John Wiley and Son.
As used herein, xe2x80x9cheteroatomxe2x80x9d refers to any atom other than a carbon atom which may be a member of a cyclic organic compound. Examples of suitable heteroatoms include nitrogen, oxygen, sulfur, phosphorous, boron, silicon, arsenic, sellenium and telluruim, especially nitrogen, oxygen and sulfur.
In preferred embodiments of compounds of Formulae (I) and (II), U, as defined in Z, is selected from one of CH2, NH, oxygen or sulfur. More preferably U is NH or oxygen. Most preferably, U is oxygen. In another preferred embodiment of Z, n+o=0, 1, 2, 3 or 4. Suitable examples of Z include xe2x80x94Oxe2x80x94CH2xe2x80x94, xe2x80x94CH2xe2x80x94Nxe2x80x94, xe2x80x94Oxe2x80x94CH2xe2x80x94Oxe2x80x94, xe2x80x94(CH2)3xe2x80x94, xe2x80x94CH2xe2x80x94NHxe2x80x94CH2xe2x80x94 or xe2x80x94CH2xe2x80x94Oxe2x80x94CH2xe2x80x94. In another preferred embodiment, n and o are both zero.
In another preferred form, V is hydrogen, iodine or bromine.
In other embodiments of Formulae (I) and (II), when W and X, together with the nitrogen and carbon atoms to which they are attached, form a saturated or unsaturated heterocyclic group, the group is preferably optionally substituted quinolinyl, optionally substituted isoquinolinyl, optionally substituted dihydroquinolinyl, optionally substituted dihydroisoquinolinyl, optionally substituted pyridyl or dihydro or tetrahydro congeners thereof, or optionally substituted phenanthridine. Preferably, W and X together with the nitrogen and carbon atoms to which they are attached, form an optionally substituted isoquinolinyl or optionally substituted dihydroisoquinolinyl group of general Formula (i): 
wherein R1-R4 and R14 are as defined for Y above, and  represents an optional double bond.
Preferably R1-R4 of Formula (i) are hydrogen; hydroxy; optionally substituted alkyl; optionally substituted alkyloxy; acyloxy; carboxy; carboxy ester, wherein the ester is preferably methyl, ethyl, propyl or butyl ester; optionally substituted amino,; carboxamido, wherein the nitrogen atom thereof is optionally substituted by one or two alkyl groups independently selected from methyl, ethyl, propyl or butyl; or sulfate. Most preferably they are hydrogen, hydroxy, methoxy, ethoxy, iso-propoxy, methyl, ethyl, propyl, acetoxy or sulfate. Preferably R14 is hydrogen or hydroxy.
In yet other embodiments of Compounds of Formulae (I) and (II), when RA1RA2Cxe2x80x94CRA3RA4 form an aryl group or an aromatic heterocyclic group, it may be an optionally substituted benzene or naphthalene ring or an optionally substituted aromatic heterocyclic group such as pyridine, furan, pyrrole or thiophene and benzene-fused analogues thereof, for example, quinoline, indole, benzofuran and benzothiophene. Attachment of the bicyclic heterocyclic group may be via the benzene or heterocyclic ring. Preferably RA1RA2Cxe2x80x94CRA3RA4 forms an optionally substituted benzene group. Preferably the substituents are hydrogen; hydroxy; optionally substituted alkyl; optionally substituted alkyloxy; acyloxy; carboxy; carboxy ester, wherein the ester is preferably methyl, ethyl, propyl or butyl ester; optionally substituted amino,; carboxamido, wherein the nitrogen atom thereof is optionally substituted by one or two alkyl groups independently selected from methyl, ethyl, propyl or butyl; or sulfate. Most preferably they are hydrogen, hydroxy, methoxy, ethoxy, iso-propoxy, methyl, ethyl, propyl, acetoxy or sulfate.
In another embodiment RA1-A4 are preferably independently selected from hydrogen, optionally substituted alkyl, optionally protected hydroxy, optionally substituted alkoxy, optionally substituted phenyl or acyloxy. In one preferred embodiment, at least one of RA1 or RA3 may be hydrogen. In another embodiment, both RA1 and RA3 are hydrogen. In yet a further embodiment, three or four of RA1-A4 are hydrogen.
In another embodiment, when RA2 and RA3 together form a bond so as to form a group RA1Cxe2x95x90CRA4, RA1 and RA4 each may be independently selected from hydrogen; hydroxy; optionally substituted alkyl; optionally substituted alkyloxy; acyloxy; carboxy; carboxy ester, wherein the ester is preferably methyl, ethyl, propyl or butyl ester; optionally substituted amin or; carboxamido, wherein the nitrogen atom thereof is optionally substituted by one or two alkyl groups independently selected from methyl, ethyl, propyl or butyl. In especially preferred forms, one or both of RA1 and RA4 are hydrogen.
When RA2 and RA3, together with the carbons to which they are attached, form a carbocyclic or heterocyclic group as defined above, preferably they form a 3 to 8-membered cyclic group, preferably 5 to 6-membered cyclic group. Preferably they form a cyclopentane, cyclohexane, cyclopentene, cyclohexene, cyclopentadiene, cyclohexadiene, tetrahydrofuran, dihydrofuran, pyrrolidine, pyrroline, pyran, dihydrophyran, tetrahydropyran or piperidene group. Preferably, RA1 and RA4 are hydrogen.
In still yet a further embodiment, Y is preferably an optionally substituted phenyl group of Formula (ii): 
Wherein R9-R13 are as defined for R1-R4 and R14 as described above.
More preferably, R9-R13 are hydrogen; hydroxy; optionally substituted alkyl; optionally substituted alkyloxy; acyloxy; carboxy; carboxy ester, wherein the ester is preferably methyl, ethyl, propyl or butyl ester; optionally substituted amino,; carboxamido, wherein the nitrogen atom thereof is optionally substituted by one or two alkyl groups independently selected from methyl, ethyl, propyl or butyl; or sulfate. Most preferably, R9-R13 are selected from hydrogen, hydroxy, methoxy, ethoxy, iso-propoxy, methyl, ethyl, n-propyl, isopropyl, acetoxy or sulphate.
Another preferred embodiment of Formula (I) is a compound of Formula (Ia) where X is hydrogen and W is a group of the formula (iii); 
wherein V is hydrogen or halogen; RB1-B4 are correspondingly defined as for RA1-A4 herein above; and
m is selected from 1, 2, 3 or 4.
Thus, in a preferred embodiment, the present invention relates to a method for the preparation of a compound of Formula (IIa): 
comprising the step of performing two intramolecular cyclizations on a compound of Formula (Ia): 
wherein:
RA1-A4, V, Y, Z are as defined above;
RB1-B4 are each independently selected from hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally protected hydroxy, optionally substituted amino, optionally substituted alkoxy, optionally substituted alkenoxy, optionally substituted alkynoxy, optionally substituted aryl, optionally substituted heterocyclyl, carboxy, carboxy ester, carboxamido, acyl, acyloxy, mercapto, optionally substituted alkylthio, halogen, nitro, sulfate, phosphate and cyano; or
RB2 and RB3 may optionally together form a bond and RA1 and RA4 are as defined above or together with the carbon atoms to which they are attached form an optionally substituted carbocyclic or heterocyclic group; or
RB2 and RB3, together with the carbon atoms to which they are attached form an optionally substituted saturated or unsaturated carbocyclic or heterocyclic group; or
RB1RB2Cxe2x80x94CRB3RB4 form an optionally substituted aryl group or aromatic heterocyclic group; and
m is selected from 1, 2, 3 or 4.
Another preferred embodiment of the invention provides an intermediate compound of Formula (Ia) 
wherein:
RA1-A4, RB1-B4, V, Y, Z and m are as defined above and optionally, one or more (CH2) groups of (CH2)m defined in formula (iii) may be optionally substituted by a group R14 as defined above.
In a preferred embodiment m is 1 or 2. Even more preferably in is 2.
In yet other embodiments of Compounds of Formulae (Ia) and (IIa), when RB1RB2Cxe2x80x94CRB3RB4 forms an aryl group or an aromatic heterocyclic group, it may be an optionally substituted benzene or naphthalene ring or an optionally substituted aromatic heterocyclic group such as pyridine, furan, pyrrole or thiophene and benzene-fused analogues thereof, for example, quinoline, indole, benzofuran and benzothiophene. Attachment of the bicyclic heterocyclic group may be via the benzene or heterocyclic ring. Preferably RB1RB2Cxe2x80x94CRB3RB4 forms an optionally substituted benzene group. Where RB1RB2Cxe2x80x94CRB3RB4 forms a benzene group (containing the substituent V) cyclization can afford a group of formula (i) as described herein above. Preferably the substituents are hydrogen; hydroxy; optionally substituted alkyl; optionally substituted alkyloxy; acyloxy; carboxy; carboxy ester. wherein the ester is preferably methyl, ethyl, propyl or butyl ester; optionally substituted amino,; carboxamido, wherein the nitrogen atom thereof is optionally substituted by one or two alkyl groups independently selected from methyl, ethyl, propyl or butyl; or sulfate. Most preferably they are hydrogen, hydroxy, methoxy, ethoxy, iso-propoxy, methyl, ethyl, propyl, acetoxy or sulfate.
In another embodiment RB1-B4 are preferably independently selected from hydrogen, optionally substituted alkyl, optionally protected hydroxy, optionally substituted alkoxy, optionally substituted phenyl or acyloxy. In one preferred embodiment, at least one of RB1 or RB3 may be hydrogen. In another embodiment, both RB1 and RB3 are hydrogen. In yet a further embodiment, three or four of RB1-B4 are hydrogen.
In another embodiment, when RB2 and RB3 together form a bond so as to form a group RB1Cxe2x95x90CRB4, RB1 and RB4 each may be independently selected from hydrogen; hydroxy; optionally substituted alkyl; optionally substituted alkyloxy; acyloxy; carboxy; carboxy ester, wherein the ester is preferably methyl, ethyl, propyl or butyl ester; optionally substituted amin or; carboxamido, wherein the nitrogen atom thereof is optionally substituted by one or two alkyl groups independently selected from methyl, ethyl, propyl or butyl. In especially preferred forms, one or both of RA1 and RA4 are hydrogen.
When RB2 and RB3, together with the carbons to which they are attached, form a carbocyclic or heterocyclic group as defined above, preferably they form a 3 to 8-membered cyclic group, preferably 5 to 6-membered cyclic group. Preferably they form a cyclopentane, cyclohexane, cyclopentene, cyclohexene, cyclopentadiene, cyclohexadiene, tetrahydrofuran, dihydrofuran, pyrrolidine, pyrroline, pyran, dihydrophyran, tetrahydropyran or piperidene group. Preferably, RB1 and RB4 are hydrogen.
Especially preferred compounds of Formula (I) have the structure of Formula (Ib) below: 
where R1-R14 are independently selected from hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally protected hydroxy, optionally substituted amino, optionally substituted alkoxy, optionally substituted alkenoxy, optionally substituted alkynoxy, optionally substituted aryl, optionally substituted heterocyclyl, carboxy, carboxy ester, carboxamido, acyl, acyloxy, mercapto, optionally substituted alkylthio, halogen, nitro, sulfate, phosphate and cyan. Preferred R1-R14 are selected from hydrogen; hydroxy; optionally substituted alkyl; optionally substituted alkyloxy; acyloxy; carboxy; carboxy ester, wherein the ester is preferably methyl, ethyl, propyl or butyl ester; optionally substituted amino, such as mono or dialkyl amino; carboxamido, wherein the nitrogen atom thereof is optionally substituted by one or two alkyl groups independently selected from methyl, ethyl, propyl or butyl; or sulfate.
More preferably R1-R13 are selected from hydrogen; hydroxy; optionally substituted alkyl, such as methyl, ethyl or propyl; optionally substituted alkyloxy such as methoxy, ethoxy, n-propoxy, iso-propoxy; acyloxy such as acetoxy; or sulfate and R14 is preferably hydrogen or hydroxy. V is as defined above, preferably hydrogen, iodine or bromine.
Thus a further preferred form of the invention provides a method of preparing a fused polycyclic pyrrole-containing compound of Formula (IIb): 
comprising the step of performing two cyclizations on a compound of Formula (Ib).
The intramolecular cyclizations of compounds of Formula (I), preferably of Formula (Ia) or (Ib), to form the polycyclic fused compounds of Formula (II), preferably of Formula (Ia) or (IIb) can be carried out by any suitable means known to those skilled in the art. Suitable methods are described below, however, any other method which will effect the desired cyclization also forms part of the present invention. It will be understood that the groups V, W, X, Y, Z, RA1-A4, RB1-B4, and R1-14 are such that they do not interfere with the cyclization process.
Where V represents a hydrogen atom, an oxidative intramolecular cyclization process, such as those described by Black et al, Tetrahedron Lett., 1989, 30, 5807 and Kita et al, Chem. Commum, 1996, 1481, may be used to effect the cyclization.
Alternatively, when V is a halogen atom, the intramolecular cyclization may proceed via the generation of a suitable radical in an analogous manner to those described by Antonio et al, Can. J. Chem., 1994, 72, 15 and Moody et al, Tetrahedron Lett., 1995, 36, 9501.
Yet another method for intramolecularly cyclizing a compound of Formula (I), when V is halogen, involves a Pd[0]-mediated cyclization. The intramolecular Pd[0]-catalyzed olefination of an organic halide (intramolecular Heck Reaction) is known to those skilled in the art and can be carried out by any suitable combination of reagents which will provide palladium in the zero state (Pd[0]).
Suitable combinations of reagents for effecting Pd[0]-catalysed cyclization are described, for example, in Burwood et al, Tetrahedron Lett., 1995, 36, 9053; Desarbe et al, Heterocycles, 1995, 41, 1987; Harayoma et al, Chem. Pharm. Bull., 1997, 45, 1723; and Grigg et al, Tetrahedron, 1995, 50, 359.
Thus, in one embodiment of the invention, Pd[0]-catalysed cyclization of Formula (I) may be effected by generating Pd[0] in situ by a combination of a Pd[II] reagent and a xe2x80x9cligandxe2x80x9d, and further providing a base for regeneration of the Pd[0] catalyst.
Suitable examples of a Pd[II]/Pd[0] reagent include, but are not limited to: Pd(OAc)2, PdCl2(CH3CN)2, PdCl2(PPh3)2, Pd(C6H5CN)2Cl2, Pd(dibenzylideneacetone)3.
Suitable examples of xe2x80x9cligandxe2x80x9d providing reagents include, but are not limited to: PPh3, P(o-tolyl)3; 1,3-bis[diphenylphosphino]propane and 1, 3-bis[diphenylphosphino]ethane.
Suitable bases for regenerating Pd[0] from Pd[II], which is formed during the Pd[0]-catalysed cyclization, include, but are not limited to; alkylamines, such as triethylamine and diisopropylethylamine; acetates, such as sodium acetate and potassium acetate; carbonates such as potassium carbonate, sodium carbonate, silver carbonate; and hydroxides such as sodium and potassium hydroxide.
When a compound of Formula (Ia) or (Ib) is treated to effect a double cyclization, to form compounds of Formula (Ia) or (IIb), the cyclizations may be effected by the radical, oxidative or Pd-mediated cyclization procedures as described above, and each cyclization may be effected in the-same, similar or different manner.
Thus, in one embodiment, the two cyclizations may be performed sequentially, in any order, and may optionally employ different reagents and conditions, for example as described above. Optionally, after one cyclization, is performed, the mono-cyclized product may be isolated before being treated under suitable sonditions to perform the second intramolecular cyclization. In another form, the xe2x80x9cdouble cyclizationxe2x80x9d may be effected in xe2x80x9cone-potxe2x80x9d, preferably under a single set of reaction conditions.
In a more preferred form, a compound of Formula (Ia), preferably (Ib), is made to undergo a xe2x80x9cdouble cyclizationxe2x80x9d to form a compound of Formula (IIa), preferably (IIb), under Pd[0]-catalysed conditions.
In an even more preferred form, both cyclizations are effected in xe2x80x9cone-potxe2x80x9d under a single set of reaction conditions.
The compounds of Formula (I), (Ia) and (Ib) may be prepared, starting from a pyrrole core, by standard procedures known to the skilled addressee for effecting substitution of the carbon atoms of the pyrrole core, for example by electrophilic aromatic substitution or halogenating the pyrrole nucleus and effecting a substitution by Stille, Suzuki, or Negishi cross-coupling reactions with stannane, boronic acid or zinc compounds such as aryl-stannanes, aryl boronic acid and aryl zinc compounds. Substitution of the N-atom can be effected by standard procedures.
One suitable approach, although by no means limiting, is depicted below in Scheme 1 which is considered to be illustrative of suitable methods for substituting the pyrrole nucleus.
It will be understood that by use of the appropriate reagents in steps used to introduce the 1-, 2-, 4-substitution pattern of the pyrrole core, for example, the phenyl containing reagents used in steps, (d), (e) and (f) wherein the phenyl moiety is further substituted as hereinbefore described, a range of substitution patterns and substituents may be introduced to form the intermediates amenable to the cyclization processes and the formation of the corresponding cyclized compounds. 
Scheme 1
Reagents and conditions: (a) Cl3CCOCl (1 mole equiv.), Et2O, 35xc2x0 C., 1 h (80%); (b) I2 (1 mole equiv.), AgO2CCF3 (1 mole equiv.), CHCl3, 18xc2x0 C., 1 h (82%); (c) K2CO3 (2M in H2O), DMSO, 18xc2x0 C., 32 h (92%); (d) (i) (COCl)2 (1.1 mole equiv.), DMF (cat.), CH2C2, 18xc2x0xc2x0 C., 2 h; (ii) o-bromophenol (1 mole equiv.), DMAP (cat.), CH2Cl2, 18xc2x0 C., 1 h (92%); (e) K2CO3 (1.14 mole equiv.), Bu4NCl (0.1 mole equiv.), DMF, 80xc2x0 C., 2 h (90%): (f) PhZnCl (1.3 mole equiv.), PdCl2(PPh3)2 (0.05 mole equiv.), THF/DMF, 18xc2x0 C., 1 h (95%); (g) Pd(OAc)2 (0.5 mole equiv.), PPh3 (1 equiv.), NaOAc (4 equiv.), DMF, 130xc2x0 C., 6 h (16%); (h) TsCl (2.4 mole equiv.), KOH (2.4 mole equiv.), Et2O, 0(copyright)18xc2x0 C., 2 h (98%).
Where the optional double bond is present, as in the compounds of Formula (II) which contain moiety of Formula (I), such as compounds of Formula (IIb), this may be introduced either by dehydrogenation of the cyclized product, or alternatively, by incorporation of the corresponding double bond into a precursor thereof. Suitable methods therefor will be known to the skilled addressee (see for example, Advanced Organic Chemistry, Reactions, Mechanisms, and Structure by Jerry March, Third Edition, Wiley Interscience). One such suitable method comprises treating the cyclized compound of Formula (IIb), with DDQ (2,3-Dichloro-5,6-dicyano-1,4-benzoqionone). For example, Lamellarin T diisopropylether (Compound 37 in Table 2) can be converted into Lamellarin W diisopropylether (Compound 11 in Table 1) by treatment with DDQ in dry chloroform at 60-65 C. (see Example 11 in WO98/50365)
WO 97/01336 (the entire contents of which are taken to be incorporated herein by reference) describes Lamellarin class compounds as having inhibitory and/or cytotoxic activity against multidrug resistant-type tumours.
Accordingly, yet another aspect of the present invention contemplates a method of treatment comprising the administration of a treatment effective amount of a compound of general Formula (II), as prepared by the methods described herein, as an active ingredient, to an animal, including a human, in need thereof.
As used herein, the term xe2x80x9ceffective amountxe2x80x9d relates to an amount of compound which, when administered according to a desired dosing regimen, provides the desired therapeutic activity. The dose will depend on the age, weight and condition of the subject and it is within the skill of the attending physician to determine suitable doasages. Dosing may occur at intervals of minutes, hours, days, weeks, months or years or continuously over any one of these periods. Suitable dosages lie within the range of about 0.1 ng per kg of body weight to 1 g per kg of body weight per dosage. Preferably, the dosage is in the range of 1 xcexcg to 1 g per kg of body weight per dosage. More preferably, the dosage is in the range of 1 mg to 1 g per dosage per kg of body weight. Suitably, dosages are in the range of about 1 mg to 500 mg per kg of body weight, such as between 1 mg and 250 mg or 1 mg and 100 mg.
In a preferred embodiment, the method of treatment relates to treating multidrug resistant tumors.
In another embodiment, the method of treatment contemplates improving the antitumor chemotherapeutic effect of multidrug resistant affected drugs.
In another preferred embodiment, the method of treatment is a method for inducing apoptosis. More preferably, the method of treatment is a method of inducing apoptosis on a multidrug resistant cell.
In another embodiment, the method of treatment contemplates modulating immunological functions.
The active ingredient may be administered in a single dose or a series of doses. While it is possible for the active ingredient to be administered alone, it is preferable to present it as a composition, preferably as a pharmaceutical composition.
Yet another aspect of the invention contemplates compositions comprising a compound of general Formula (II), as prepared according to the present invention, together with a pharmaceutically acceptable carrier, excipient or diluent.
The carrier must be pharmaceutically xe2x80x9cacceptablexe2x80x9d in the sense of being compatible with the other ingredients of the composition and not injurious to the subject. Compositions include those suitable for oral, rectal, nasal, topical (including buccal and sublingual), vaginal or parental (including subcutaneous, intramuscular, intravenous and intradermal) administration. The compositions may conveniently be presented in unit dosage form and may be prepared by any methods well known in the art of pharmacy. Such methods include the step of bringing into association the active ingredient with the carrier which constitutes one or more accessory ingredients. In general, the compositions are prepared by uniformly and intimately bringing into association the active ingredient with liquid carriers or finely divided solid carriers or both, and then if necessary shaping the product.
Compositions of the present invention suitable for oral administration may be presented as discrete units such as capsules, sachets or tablets each containing a predetermined amount of the active ingredient; as a powder or granules; as a solution or a suspension in an aqueous or non-aqueous liquid; or as an oil-in-water liquid emulsion or a water-in-oil liquid emulsion. The active ingredient may also be presented as a bolus, electuary or paste.
A tablet may be made by compression or moulding, optionally with one or more accessory ingredients. Compressed tablets may be prepared by compressing in a suitable machine the active ingredient in a free-flowing form such as a powder or granules, optionally mixed with a binder (e.g inert diluent, preservative disintegrant (e.g. sodium starch glycolate, cross-linked polyvinyl pyrrolidone, cross-linked sodium carboxymethyl cellulose) surface-active or dispersing agent. Moulded tablets may be made by moulding in a suitable machine a mixture of the powdered compound moistened with an inert liquid diluent. The tablets may optionally be coated or scored and may be formulated so as to provide slow or controlled release of the active ingredient therein using, for example, hydroxypropylmethyl cellulose in varying proportions to provide the desired release profile. Tablets may optionally be provided with an enteric coating, to provide release in parts of the gut other than the stomach.
Compositions suitable for topical administration in the mouth include lozenges comprising the active ingredient in a flavoured base, usually sucrose and acacia or tragacanth gum; pastilles comprising the active ingredient in an inert basis such as gelatin and glycerin, or sucrose and acacia gum; and mouthwashes comprising the active ingredient in a suitable liquid carrier.
Compositions for rectal administration may be presented as a suppository with a suitable base comprising, for example, cocoa butter.
Compositions suitable for vaginal administration may be presented as pessaries, tampons, creams, gels, pastes, foams or spray formulations containing in addition to the active ingredient such carriers as are known in the art to be appropriate.
Compositions suitable for parenteral administration include aqueous and non-aqueous isotonic sterile injection solutions which may contain anti-oxidants, buffers, bactericides and solutes which render the composition isotonic with the blood of the intended recipient; and aqueous and non-aqueous sterile suspensions which may include suspending agents and thickening agents. The compositions may be presented in unit-dose or multi-dose sealed containers, for example, ampoules and vials, and may be stored in a freeze-dried (lyophilised) condition requiring only the addition of the sterile liquid carrier, for example water for injections, immediately prior to use. Extemporaneous injection solutions and suspensions may be prepared from sterile powders, granules and tablets of the kind previously described.
Preferred unit dosage compositions are those containing a daily dose or unit, daily sub-dose, as herein above described, or an appropriate fraction thereof, of the active ingredient.
It should be understood that in addition to the active ingredients particularly mentioned above, the compositions of this invention may include other agents conventional in the art having regard to the type of composition in question, for example, those suitable for oral administration may include such further agents as binders, sweeteners, thickeners, flavouring agents disintegrating agents, coating agents, preservatives, lubricants and/or time delay agents. Suitable sweeteners include sucrose, lactose, glucose, aspartame or saccharine. Suitable disintegrating agents include corn starch, methylcellulose, polyvinylpyrrolidone, xanthan gum, bentonite, alginic acid or agar. Suitable flavouring agents include peppermint oil, oil of wintergreen, cherry, orange or raspberry flavouring. Suitable coating agents include polymers or copolymers of acrylic acid and/or methacrylic acid and/or their esters, waxes, fatty alcohols, zein, shellac or gluten. Suitable preservatives include sodium benzoate, vitamin E, alpha-tocopherol, ascorbic acid, methyl paraben, propyl paraben or sodium bisulphite. Suitable lubricants include magnesium stearate, stearic acid, sodium oleate, sodium chloride or talc. Suitable time delay agents include glyceryl monostearate or glyceryl distearate.
The present invention also provides the use of a compound of general Formula (II), as prepared according to the present invention, in the manufacture of a medicament for treatment of an animal or human in need thereof.
Another aspect of the invention contemplates an agent for the treatment of an animal or human in need thereof comprising a compound of general Formula (II), as prepared according to the present invention.
In a first embodiment, the agent is for treating multidrug resistant tumors.
In another embodiment the agent is for inducing apoptosis on a multi-drug resistant cell.
In yet another embodiment, the agent is for improving the anti-tumor chemotherapeutic effect of multidrug resistant affected drugs.
A further embodiment is an agent for modulating immunological functions.
Suitable, although by no means limited, examples of compounds which may be prepared via the intermediates of the present invention are depicted below in Tables 1 and 2:
The invention will now be described with reference to the following Examples. However, it is to be understood that these do not supercede the generality of the preceding description.